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A properly pruned tree looks as natural as possible; that is to say, the tree’s appearance reflects its fundamental form and character. The pruner must be sensitive to maintaining this structural integrity, in addition to knowing a bit about tree biology and proper pruning principles!

The Pacific Northwest Chapter of the International Society of Arboriculture (PNW-ISA) is a member organization for arborists and urban foresters. We bring together professionals from Alaska, Idaho, Oregon, Washington, and British Columbia. Since 1979, we have been a resource and advocate for the green industry.

We had a viewer send in this photo of a tree in Cedar Canyon near Banks, Oregon. We posted this to the OPB/ Oregon Field Guide Facebook page and now I feel a responsibility to give folks an accurate ID of what is causing this strange formation atop the tree. Mistletoe? Witch's Broom? Something else?...

Is it true that white paper birch in the Willamette Valley have been infested with insect like beetle? I wanted to plant one this spring and my yard maintenance service told me I should consider a different type due to the insect problem.

This is a bilingual publication (English and Spanish) for landscape workers and the public to help them protect Oregon trees and forests from this damaging pest. Includes insect identification, host plants, signs and symptoms, and what to do if you suspect that an insect you've seen is EAB.
Esta...

This is a bilingual publication (English and Spanish) for landscape workers and the public to help them protect Oregon trees and forests from this damaging pest. Includes insect identification, host plants, signs and symptoms, how to spot an ALB (including insects that resemble ALB), and what to do...